Difference Between Somatostatin and Somatotropin

The key difference between somatostatin and somatotropin is that somatostatin is a growth hormone-inhibiting hormone that works as a somatotropin release inhibiting factor. Meanwhile, somatotropin is a growth hormone that stimulates the growth of essentially all tissues of the body.

Hormones are chemical signalling molecules that carry messages between different parts of the body. They are mainly secreted by the endocrine glands into the bloodstream and transported through circulation. These hormones affect cellular processes including mainly growth and development, reproduction and metabolism. Somatotropin is the growth hormone that stimulates the growth of almost all tissues in our body. On the other hand, somatostatin is the somatotropin inhibitory factor or growth hormone inhibiting hormone which inhibits somatotropin secretion. Both somatotropin and somatostatin are peptide hormones.

CONTENTS

1. Overview and Key Difference
2. What is Somatostatin 
3. What is Somatotropin
4. Similarities Between Somatostatin and Somatotropin
5. Side by Side Comparison – Somatostatin vs Somatotropin in Tabular Form
6. Summary

What is Somatostatin?

Somatostatin is a peptide hormone named as growth hormone inhibiting hormone. In simple words, somatostatin is the somatotrophin release inhibiting factor. Thus, the main function of somatostatin is the inhibition of the secretion of growth hormone (somatotropin) from the somatotroph cells. Moreover, it inhibits the secretion of insulin, glucagon, and gut hormones. It is also generally inhibitory to gastrointestinal motility and exocrine secretion. Furthermore, somatostatin has pronounced anti-proliferative effect. It is also capable of promoting cellular apoptosis

Figure 01: Somatostatin

Besides, this hormone is released by the neuroendocrine cells of hypothalamus. It is found in the central and peripheral nervous systems. It is also found in D (δ) cells of the pancreatic islets and gastrointestinal tract. Structurally, somatostatin is a peptide composed of 14 amino acid molecule. There are two forms of somatostatin: somatostatin 14 and somatostatin 28.

What is Somatotropin?

Somatotropin is the growth hormone secreted by the pituitary gland, especially by the anterior pituitary cells called somatotrophs. This hormone is responsible for the growth of all tissues in our body. It also stimulates cell reproduction and cell regeneration. Somatotropin carries out its job by stimulating protein synthesis and increasing fat breakdown to provide the energy necessary for tissue growth. Structurally, somatotropin is a peptide composed of 191 amino acids molecule.

Figure 02: Somatotropin

The growth hormone-releasing hormone stimulates the release of somatotropin, and meanwhile, the somatostatin inhibits the secretion of somatotropin. Somatotropin deficiency causes short stature and dwarfism. Therefore, it can be treated by the injections containing growth hormone. On the other hand, excess somatotropin production is harmful, and it can cause tumour development in somatotroph cells of the pituitary gland.

What are the Similarities Between Somatostatin and Somatotropin?

• Both somatostatin and somatotropin are peptide hormones composed of amino acid molecules.
• Somatostatin inhibits the secretion of somatotropin.
• Moreover, both are released by the two different endocrine glands in our brain.

What is the Difference Between Somatostatin and Somatotropin?

Somatostatin is a peptide hormone that works as a growth hormone inhibiting hormone. Meanwhile, somatotropin is the human growth hormone that stimulates the growth of all tissues of the body. So, this is the key difference between somatostatin and somatotropin.

Moreover, somatostatin is secreted by the hypothalamus while somatotropin is secreted by the pituitary gland. Thus, this is also a difference between somatostatin and somatotropin. Besides, somatostatin is composed of 14 and 28 amino acid molecules, while somatotropin is composed of 191 amino acid molecules.

Summary – Somatostatin vs Somatotropin

Somatostatin is an inhibitory hormone. It is also called the growth hormone inhibiting hormone or somatotropin release inhibitory factor. As the name suggests, somatostatin inhibits the release of somatotropin. In contrast, somatotropin is the human growth hormone secreted by the somatotrophs of the anterior pituitary gland. It is a peptide hormone which is responsible for the growth of all tissues of our body. So, this is the summary of the difference between somatostatin and somatotropin.

Reference:

1. Utiger, Robert D. “Growth Hormone.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 4 Apr. 2018, Available here.
2. “Somatostatin.” Somatostatin – an Overview | ScienceDirect Topics, Available here.

Image Courtesy:

1. “Somatostatin” By Ed (Edgar181) – Own work (Public Domain) via Commons Wikimedia
2. “Somatotropine” (Public Domain) via Commons Wikimedia

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